Chain stabilizing chain saw sprockets

ABSTRACT

A method of supporting a saw chain on a chain saw sprocket wherein saw chain tangs are received in a series of open sided tang receiving recesses of the sprocket and wherein the saw chain is cyclically stabilized by disposing a saw chain tang in a close sided tang receiving recess of the sprocket. A sprocket apparatus including integrated, open sided and at least partially closed pocket means which interact to concurrently (1) stabilize and center a saw chain on the sprocket so as to minimize or eliminate wave-type vibration in the saw chain, (2) reduce friction between the sprocket and saw chain while effecting stabilization, and (3) facilitate the removal of cuttings from the sprocket while effecting stabilization.

United States Patent n 1 3,683,980 Gasner [451 Aug. 15, 1972 CHAIN STABILIZING CHAIN SAW Primary Examiner-Donald R. Schran SPROCKETS Attorney-Burns, Doane, Swecker & Mathis [72] Inventor: William L. Gasner, Gardena, Calif. [57] ABSTRACT [73] Asslgnee' Corponuon L05 A method of supporting a saw chain on a chain saw g sprocket wherein saw chain tangs are received in a se- [22] Filed: Feb. 26, 1971 ries of open sided tang receiving recesses of the sprocket and wherein the saw chain is cyclically stabil- [211 YN l19171 ized by disposing a saw chain tang in a close sided tang receiving recess of the sprocket. A sprocket apparatus including integrated, open sided and at least partially closed pocket means which in- [58] new of Search "143/32 74/243 243 teract to concurrently (l) stabilize and center a saw chain on the sprocket so as to minimize or eliminate [56] References C'ted wave-type vibration in the saw chain, (2) reduce fric- UNITED STATES PATENTS tion bemeenthe sproiclggarfid slatv chaliln while egflectg mg sta uzation, an aciiate t e remov o lg;

cuttings from the sprocket while effecting stabiliza- 7 a I Ll I v 3,498,346 3/1970 Gasner et a1. ..143/32 R 5 Claim, 9 Drawing; Figures Patented Aug. 15, 1972 3,683,980

3 Sheets-Sheet 1 \NVENTOR WILLIAM L GASNER ATTORNEYS Patented Aug. 15, 1972 3 Sheets-Sheet 2 Patented Aug. 1972 3,683,980

3 Sheets-Sheet 5 (a 5N E N H- N 2 N /I V IIIA //I 1"// fish] 1 CHAIN STABILIZING CHAIN SAW SPROCKE'IS GENERAL BACKGROUND, OBJECTS AND SUMMARY OF INVENTION The chain saw industry has devoted substantial efforts over the past several years to the development of improved chain saw components, with a view to reducing chain saw cost and improving operational reliability.

Part and parcel of this effort has been the development of improved saw chain sprocket means.

One such improved chainsaw sprocket means is disclosed in a Gudmundsen U.S. Pat. No. 3,279,272 1966).

The Gudmundsen sprocket is characterized by a one piece'body which defines a series of circumferentially spaced, open sided, saw chain tang receiving recess means. In the Gudmundsen sprocket, the recess means have sides which open axially of the sprocket, with the direction of recess means opening circumferentially alternating in opposite axial directions. The Gudmundsen unit is characterized by low fabrication cost, effective saw chain support, and driving characteristics, and uniquely effectivecutting removal action.

Another advance in the chain saw sprocket art is evidenced by Gasner et a]. US. Pat. No. 3,498,346 (1970). This Gasner et al. patent discloses a chain saw sprocket characterized by features substantially different in many respects from those incorporated in the Gudmundsen sprocket.

The Gasner et a]. sprocket is characterized by at least partially closed saw chain tang receiving recess means.

Each such recess means is operable to engage either side of a chain saw tang. One side of each such recess means is provided with a cutting outlet at the recess base which circumferentially and radially enlarges in a direction extending outwardly of the recess means.

This Gasner et al. sprocket is characterized by effective cutting removal action and chain saw stabilization.

With the art now having recourse to improvements exemplified by the disclosures of the Gudmundsen and Gasner et al. patents, it would be desirable at times, because of chain saw dimensions and desired radii of curvature of saw chains as they pass around drive sprockets, to support saw chains with sprockets having an odd number of tang receiving recesses. For example, instead of supporting a chain saw with a sprocket hav-' ing six tang receiving recesses as shown in the aforesaid Gudmundsen patent, it may be desirable to support a saw chain with a sprocket having seven tang receiving recess means.

While such a mode of support may be desired, it would be concurrently desirable to maintain the efl'ec tive cutting removal action and low frictional interaction between a saw chain and sprocket which would result from the open sided pocket arrangement featured in the Gudmundsen patent.

At the same time, it would be desirable, at least to some extent, to achieve the uniquely effective saw chain stabilization which results from use of at least partially closed tang receiving recess means as disclosed in the aforesaid Gasner et al patent. This would prevent or minimize the generation or transmission of chain whipping or sinusoidal wave patterns.

Heretofore, the art has failed to realize how these overall objectives could be accomplished, particularly when the approaches of Gudmundsen and Gasner et al are seemingly diverse, i.e. one emphasizing open sided tang receiving recess means and the other emphasizing at least partially closed tang receiving recess means.

This invention constitutes a discovery as to how the basic objectives outlined above can be effectively integrated and accomplished, while producing a synergistic efl'ect heretofore not realized, namely, optimum cutting removal action in a sprocket and optimtun saw chain support but with the sprocket being nevertheless operable to effectively dampen or eliminate wave-type saw chain vibrations.

In accomplishing certain of these objectives, a method is presented for stabilizing and supporting a saw chain having sprocket engaging tangs on a chain sawsprocket. In the practice of this method, a plurality of saw chain tangs are supported in a plurality of open sided tang receiving recess means carried by a chain saw sprocket. At least periodically during rotation of the sprocket, at least one saw chain tang is supported in an at least partially closed tang receiving recess means, with this at least partially closed tang receiving recess means being concurrently operable to engage either opposite side of this saw chain tang. The supporting of tangs in the open sided recess means is effected concurrently with the supporting of at least one tang in the at least partially closed tang receiving recess means.

Apparatus objectives of the invention are achieved by a combination of open sided and at least partially closed saw chain tang receiving recess means in a sprocket hub. This combination of open sided and at least partially closed recess means defines friction reducing and chain centering means including a plurality of saw chain tang engaging surfaces contained in tang receiving recess means. These recess means have diverse saw chain lateral movement restraining properties, i.e. some recess means restrain tangs on one side only while at least one recess means restrains a tang on each tang side.

In addition, the combination of open sided and at least partially close sided tang receiving recess means provides tang pocket clearing and chain saw stabilizing means and further provides wave vibration dampening means.

In a related apparatus aspect of the invention, the at least partially closed tang receiving recess means is provided with a cutting discharge outlet means which is both coextensive with the recess means base and diverges outwardly of the recess in both circum' ferential and radial directions.

Having generally summarized the invention, detailed aspects of the invention will be considered with reference to the appended drawings. In this connection it will be recognized that the drawings provide an illustration of a preferred embodiment of the invention but are not restrictive with respect to the scope of the invention.

THE DRAWINGS FIG. 1 provides a fragmentary, perspective view of a representative chain saw in which the sprocket concept of the present invention may be utilized;

FIG. 2 provides an enlarged, fragmentary view of the portion of the FIG. 1 chain saw where a saw chain is drivingly supported by an engine and/or clutch driven sprocket;

FIG. 3 provides a still further enlarged, side elevational view of the saw chain supporting-and driving sprocket shown in FIG. 2;

FIG. 4 provides a side elevational view of the FIG. 3 sprocket, viewing the FIG. 3 sprocket from the right;

FIG. 5 provides a transverse sectional view of the FIG. 3 sprocket as viewed along section line 5-5 of FIG. 3;

FIG. 6 provides a transverse sectional view of the FIG. 3 sprocket as viewed along section line 6-6 of FIG. 3;

FIG. .7 provides a transverse sectional view of an at least partially closed, chain stabilizing tang receiving recess means of the FIG. 3 sprocket as viewed along section line 7-7 of FIG. 3;

FIG. 8 provides a schematic view of the manner in which the open sided recess means and an at least partially closed recess means of the FIG. 3 sprocket cooperate to facilitate cutting removal, reduce friction, and stabilize and center a cutting chain saw as to eliminate or minimize wave or sinusoidal type vibration therein; and

FIG. 9 schematically illustrates the manner in which,

under certain adverse conditions, sinusoidal vibration waves may be permitted by an open sided, tang receiving recess means arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Prior to describing distinguishing aspects of the present invention, it will facilitate the overall discussion to reviewa representative chain saw in which the invention may be incorporated.

As shown in FIG. 1, chain saw 1 includes an engine and drive assembly 2 and a fuel tank and carburetor assembly 3. Assembly 3 may cooperate with transversely extending handle means 4 and longitudinally extending handle means 5 to provide a cradle-like assembly, resiliently supporting the engine-drive'assembly 2.

Engine-drive assembly 2 supports a guide bar 6, the edge or periphery of which supports a cutter chain or saw chain 7.

The general disposition of components l-7 may correspond to the arrangement shown, for example, in Frederickson et al. US. Pat. No. 3,542,095. However, as will be apparent, the chain saw 1 shown in FIG. 1 is merely exemplary in nature, and the present invention may be practiced with a wide variety of chain saws either resiliently cradled or lacking such resilient cradling.

As shown in FIG. 2, guide bar 6 is connected to the engine and drive assembly 2 so as to be longitudinally adjacent a saw chain driving and supporting sprocket 8.

Cutter chain 7 extends from the upper and lower guide track portions 9 and 10 of guide bar 6 around the periphery of sprocket 8, as generally shown in FIG. 2.

Sprocket chain 7 may be defined by right-handed cutter links 11, left-handed cutter links 12, centerlinks 13 and side links 14. The various links 11-14 are interconnected by pin or pivot means in the manner generally described in the aforesaid Gudmundsen US. Pat. No. 3,279,272.

The chain arrangement shown in FIG. 2, and the mode of peripheral engagement between the base portions of the links 1 1, 12 and 14 and peripheral, rim portion 15 of the sprocket 8 may be identical to the corresponding arrangements and mode of engagement described in the Gudmundsen patent. While rim portion 15 is somewhat circumferentially undulating in character, it is disposed in general alignment with a cylindrical plane. I

The sprocket 8 may be driven clockwise by the engine and drive assembly of the chain saw 1 so as to induce the directions of cutter chain movement shown in FIG. 2. This movement is efi'ected by circumferentially spaced and generally radially outwardly opening, tang receiving recess means carried by the sprocket 8, each of which is operable to receive a tang portion 16 of a center link 13.

This general mode of chain driving and support by interaction between tangs. l6 and recess end walls may be identical to that described in the aforesaid Gudmundsen patent.

In view of the basic similarities between the exemplary, chain structure and chain driving and supporting arrangement of FIG. 2 and that of the Gudmundsen patent, the entire disclosure of this Gudmundsen US. Pat. No. 3,279,272 is herein incorporated by reference, insofar as it is relevant to. aspects of the chain saw 1 previously or subsequently discussed.

RECESS MEANS STRUCTURE OF STABILIZING SPROCKET -With the general context of the invention having been delineated, it now becomes appropriate to consider the structure of the sprocket 8 itself.

Structural aspects of the sprocket 8 are delineated in FIGS. 3-7.

' Before discussing such structure, it is appropriate to note that sprocket 8 may be fabricated in one piece, utilizing the mass production, fabrication techniques described, for example, in column 4, lines 32-52 of the aforesaid Gudmundsen patent.

Thus, sprocket 8 may comprise a hub portion 17 and a series of circurnferentially spaced, generally radially outwardly opening, open sided, tang receiving recesses or recessv means 18.

Hub 17 may be keyed to a drive shaft of assembly 2 and/or may be secured to a drive shaft of assembly 2 by way of an appropriate, centrifugally responsive clutch means, if desired.

As shown in FIG. 3, six such open sided recess means 18a-18 are provided. The recess means 18a-18f open axially of the hub 23 in circumferentially alternating directions. That is to say, the recesses 18a, 18c and 18e open toward one side of the hub 8 while the other circumferentially interposed recesses 18b, 18d and 18f open toward the other side of the hub 8.

To facilitate reference to the drawings, the base defining wall means 20 and 21 associated with recess means 180, 18c and 18e may be denominated wall means 20a and 21a while the corresponding wall means associated with recess means 18b, 18d and 18f may be denominated as wall means 20b and 21b.

Similarly, the side wall means 19 associated with recess means 18a, 18c and 18e may be denominated wall means 19a while the corresponding side wall means associated with recess means 18b, 18d and 18f may be denominated with the reference numeral 19b.

Each recess 18 is defined by a single side wall 19 and base defining wall means 2% and 21 which extend parallel to, and converge toward, the axis of hub rotation 23. As shown in FIG. 6 in connection with a representative recess 18, one side 24 of each such open sided recess means 18 is wholly unobstructed, i.e. on the open side of this recess 18, (the right side of the recess shown in FIG. 6, for example), there is no circumferentially ex tending wall portion interconnecting recess defining end wall means and 21.

Sprocket 8 is also provided with one at least partially closed, tang'receiving recess means 25. Thisstabilizing, wave vibration dampening, recess means 25 includes base or recess end defining wall means 26 and 27. Wall means 26 and 27 converge inwardly from the recess mouth 28 toward the axis of hub rotation 2.3 and extend parallel to this axis. One side of recess 25 is closed by a circumferentially extending side wall 29. The opposite side is'partially closed by a circumferentially extending web means 30.

Wall means 29 is circumferentially aligned with wall means 19a of the recesses 18a, 18c, and 18e. Similarly, the recess facing surface portion 31 of web means 30 is circumferentially aligned with wall means 1% of recess means 18b, 18d and 18f. i

' Thus, it will be appreciated that the portion of sprocket 8 which defines side wall 31 of recess 25 extends counterclockwise as shown in FlG. 3 so as to In a somewhat similar sense, the radially outermost edge portion 36 of outlet 32, as defined by the radially innermost portion of web means 34), may be chamfered or rounded. This causes outlet 32 to generally diverge along a direction extending axially outwardly of recess 25.

SYNERGISTIC ACTION In summary, it will be recognized that the recess means 18 and 25 cooperate to produce friction reducing and chain centering means including sawchain tang engaging surfaces 21 and 27. These surfaces are disposed in tang receiving recess means 25 and 18, respectively, which have diverse, lateral movement restraining properties in relation to chain tangs. The recess means 18 effect lateral restraint in one direction only while the recess means effect bidirectional lateral restraint operable with respect to each side of a tang.

Thus, as shown in FIG. 2, ofthe tangs 16a, 16b, 16c, 16d and ltie received in various recess means l8 and 25, some but not all of these tangs are contained in the define the closed side wall portion 19b of recess means Somewhat similarly, the body portion of hub means 8 which defines wall means 29 extends circumferentially clockwise as shown in H6. 3 to define theclosed side wall portion 19a of recess means l8a.

All of the various wall means 29, 30, 19a and 1912 may be peripherally beveled, as exemplified by reference character B and as shown in FlGS. 3-6, in order to facilitate the entry of the tang portions 16 of the links 13 into the various recesses 18 and 25. 7

The axial location of the wall means 29, 31, 19a and CUTTING OUTLET Recess means 25 is provided on at least its outer side with a cutting discharging outlet means 32.

Each such outlet means 32, as shown in FIG. 3, is fully coextensive with a base or root portion 33 of the recess means 25. Generally axially outwardly extending and diverging, chamfered wall portions 34 and 35 provide circumferentially spaced, side wall portions of outlet 32. These circumferentially diverging side wall portions 34 and 35 extend directly from, i.e. do not circumferentially overlap, the recess base or end wall defining wall portions 27 and 26.

and chain saw stabilizing means where a series of the recess means 18 associated'with tangs 16d-led circumferentially alternate with the recess means 25 as sociated with the tank Me. in this combination, the wall means 29 and 31 of recess 25 are operable to an gage opposite sides of the tang lee, while the adjacent recess 18a is operable to engage only one side of the tang ltid.

It will additionally be recognized that the open sided and at least partially close sided recess means uniquely cooperate to define a wave vibration dampening means.

ln this wave dampening means the at least partially closed recess means 25 is circumferentially displaced, in opposite circumferential directions, from tang receiving recess means llda and 18f.

The vibration dampening means operates-to dampen out any sinusoidal vibration wave within the chain 7 by virtue of the concurrent engageability of the wall means 311 and 29 with either opposite side of a tang such as the tang loe shown in FIG. 2.

ln practicing the saw chain support method of this invention, a saw chain 7 is supported on sprocket 8 as shown in FIG. 2.

in this mode of support the tangs low-led are supported in a plurality of open sided tang receiving recess means 18.

As shown in H6. 2, at least periodically during rotation of the sprocket 8 one tang, such as the tang Me, is supported in the at least partially closed tang receiving recess means 25, with the wall means 29 and 31 being concurrently operable to engage either opposite side of the tang lee.

These tang supporting steps are concurrently effected so as to synergistically integrate the functional advantages of open sided, and at least partially close sided, recess support for saw chain tangs.

The significance of these method aspects of the invention may be better appreciated. by reference to FIG. 8.

As shown in FIG. 8, it will be recognized that any sinusoidal vibration pattern which might be permitted by the alternately directed, opening characteristics of the recesses 18a-18f will be suppressed by the engageability of side walls 31 and 29 with opposite sides of a tang l6.

While this vibration suppression phenomena is achieved, the open sided nature of the recesses 18a18f will ensure effective removal of cuttings from the sprocket and will minimize frictional interaction between the sprocket and chain.

In addition, the walls 29 and 31 will function, on a cyclic basis, to ensure axial centering of the saw chain relative to the tang receiving recess zone of the sprocket 8, i.e. the circumferential zone of recess means 18 and 25.

In the absence of the restraint afforded by recess means 25, a sinusoidal saw chain vibration pattern,

.shown schematically in phantom lines in FIG. 9, could conceivably take place, at least for limited periods of time or as a transient phenomena, so as to roughen chain operation, generate excessive wear, etc.

OVERALL ADVANTAGES AND SUMMARY OF INVENTION In large part, the major advantages of this invention have been demonstrated through the foregoing discus- SlOl'l.

Principal advantages reside in the provision of a structure which, contrary to the prior art, teaches effective integration of beneficial aspects of open sided tang receiving recess means and close sided tang receiving recess means.

The invention further teaches the manner in which a sprocket bearing an odd number of tang receiving recesses may be effectively employed while retaining and utilizing the advantages of open sided recess means as featured in the aforesaid Gudmundsen patent. The failure of the prior art to recognize the manner in which this could be accomplished is evidenced by prior patents such as the Kaisser et al. US. Pat. No. 3,491,806, where only at least partially closed recess means are consistently employed in an odd number of recess configurations.

In summary, the combination of open sided and close sided tang receiving recess means uniquely provides friction reduction and chain centering action, minimization and/or elimination of sinusoidal or wavetype vibrations, and ensures optimum cutting clearing action. Further, the manner in which the enlarging outlet 32 is coextensive with the base and bulk of the outer side of the recess 25 produces substantially the open sided recess phenomena of the aforesaid Gudmundsen patent.

As will be apparent from the foregoing discussion, this sprocket concept is advantageously utilized in thecontext of a chain saw drive sprocket. However, conceivably, the same concept could be utilized in the context of the nose wheel of a roller nose type guide bar.

At various points during the discussion, reference has been made to particular geometric aspects of the invention. For purposes of definition, it will be recognized that axial" is utilized in the extent of extending longitudinally of axis of rotation 23. Circumferential is used in the sense of extending circurnferentially about the axis 23. The term side is used in the sense of defining surfaces facing axially of axis 23. The term lateral is used in the sense of extending or facing longitudinally of axis 23.

, Having described the invention in detail and set forth its advantage, those familiar with this disclosure and the chain saw art may envision additions, deletions, substitutions, or other modifications which would fall within the purview of the invention as set forth in the appended claims.

I claim:

1. In a sprocket operable to support a saw chain having sprocket engaging tangs, the improvement comprismg:

hub means;

a plurality of open sided saw chain tang receiving recess means spaced circumferentially about said hub means and opening generally radially out- 1 wardly thereof,

said open sided recess means each including at least one unobstructed, laterally open side;

at least one partially closed saw chain tang receiving recess means carried by said hub means and opening generally radially outwardly thereof,

said atleast partially closed tang receiving recess means having side wall portionsoperable to engage opposite sides of a saw chain cutter tang;

friction reducing and chain centering means including a plurality of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw chain, lateral movement restraining properties,

less than all of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and

at least one of said tang engaging surfaces being contained in an at least partially closed tan receiving recess means;

tang pocket clearing and saw chain stabilizing means including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess,

said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and

wave vibration dampening means including said at least one partially closed tang receiving recess means having side wall portions operable to engage opposite sides of a saw chain tang,

said at least partially closed tang receiving recess means being circumferentially displaced from at least one of said open sided tang receiving recess means.

2. In a sprocket operable to support an articulated saw chain having sprocket engaging tangs, the improvement comprising:

hub means;

a plurality of open sided, saw chain tang receiving, recess means spaced circumferentially about said hub means and opening generally radially outwardly thereof,

said open sided recess means each including at legst one wholly unobstructed, laterally open si e; at least one partially closed saw chain tang receiving recess means opening generally radially outwardly thereof said at least partially closed tang receiving recess means having axially spaced side wall portions operable to engage opposite sides of a saw chain cutter tang; friction reducing and chain centeringmeans includf ing an odd number of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw chain, lateral movement restraining properties, some, but not all, of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and i 1 at least one of said tang engaging surfaces being contained in an at least partially closed tang :receivmg recess means; tang pocket clearing and saw chain stabilizing means including I a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess means said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and wave vibration dampening means including said at least partially closed tang receiving recess means having side wall portions operable to engage op posite sides of a saw chain tang, said at least partially closed tang receiving recess means being displaced in opposite circumferential directions from at least some of said open sided tang receiving recess means. 3. A sprocket as described in claimZ further comprising:

cutting discharging, outlet means carried by at least one side wall portion of said at least partially closed tang receiving recess means;

said outlet means being circumferentially coextensive with a radially inwardly converging base portion of said at least partially closed recess means and diverging circumferentially and radially of said sprocket means in a direction axially outwardly thereof; and

common body means unitizing and defining said at least partially closed tang receiving recess means and said open sided, chain saw tang receiving recess means.

4. In a sprocket operable to support and drive an articulated saw chain having sprocket engaging tangs carried by chain links, the improvement comprising:

hub means;

an even numbered plurality of open sided, saw chain tang receiving, recess means spaced circumferentially about said hub means and opening generally radially outwardly thereof,

said open sided recess means each including at least one wholly unobstructed, laterally open side;

a single, partially closed, saw chain tang receiving recess means opening generally radially outwardly thereof, said at least partially closed "tang receiving rece means having axially spaced side wall portions operable to engage opposite sides of a saw chain cutter tang; friction reducing and chain centering means including an odd number of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw' chain, lateral movement restraining properties,

some, but not all, of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and

at least one of said tang engaging surfaces being contained in an at least partially closed tang receiving recess means;

tang pocket clearing and saw chain stabilizing mean including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess means,

said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and

wave vibration dampening means including said at least partially closed tang receiving recess means having side wall portions operable to engage opposite sides of a saw chain tang,

said at least partially closed tang receiving recess means being displaced in opposite circumferential directions from at least some of said open sided tang receiving recess means, and

' said at least partially closed tang receiving recess means having axially spaced side wall portions extending circumferentially in opposite directions to define closed side wall portions of open sided recess means displaced circumferentially from said at least partially closed tang receiving recess means. 5. In a chain saw including a sprocket drivingly supporting an articulated saw chain having sprocket engaging tangs, the improvement in said chain saw comprising:

articulated saw chain means including sprocket engaging tangs;

sprocket hub means;

a plurality of open sided, saw chain tang receiving,

recess means spaced circumferentially about and carried by said hub means and opening generally radially outwardly thereof, said open sided recess means each including at least one wholly unobstructed, laterally open side;

at least one partially closed saw chain tang receiving recess means carried by said lhub means and opening generally radially outwardly thereof, said at least partially closed tang receiving recess means having axially spaced side wall portions engageably disposed on opposite sides of a saw chain cutter tang;

friction reducing and chain centering means includtang pocket clearing and saw chain stabilizing means including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess means said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and

wave vibration dampening means including said at least partially closed tang receiving recess means having side wall operable to engage opposite sides of a saw chain tang,

said at least partially closed tang receiving recess means being displaced in opposite circumferential directions from at least some of said open sided tang receiving recess means.

l l I I 

1. In a sprocket operable to support a saw chain having sprocket engaging tangs, the improvement comprising: hub means; a plurality of open sided saw chain tang receiving recess means spaced circumferentially about said hub means and opening generally radially outwardly thereof, said open sided recess means each including at least one unobstructed, laterally open side; at least one partially closed saw chain tang receiving recess means carried by said hub means and opening generally radially outwardly thereof, said at least partially closed tang receiving recess means having side wall portions operable to engage opposite sides of a saw chain cutter tang; friction reducing and chain centering means including a plurality of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw chain, lateral movement restraining properties, less than all of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and at least one of said tang engaging surfaces being contained in an at least partially closed tang receiving recess means; tang pocket clearing and saw chain stabilizing means including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess, said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and wave vibration dampening means including said at least one partially closed tang receiving recess means having side wall portions operable to engage opposite sides of a saw chain tang, said at least partially closed tang receiving recess means being circumferentially displaced from at least one of said open sided tang receiving recess means.
 2. In a sprocket operable to support an articulated saw chain having sprocket engaging tangs, the improvement comprising: hub means; a plurality of open sided, saw chain tang receiving, recess means spaced circumferentially about said hub means and opening generally radially outwardly thereof, said open sided recess means each including at least one wholly unobstructed, laterally open side; at least one partially closed saw chain tang receiving recess means opening generally radially outwardly thereof said at least partially closed tang receiving recess means having axially spaced side wall portions operable to engage opposite sides of a saw chain cutter tang; friction reducing and chain centering means including an odd number of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw chain, lateral movement restraining properties, some, but not all, of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and at least one of said tang engaging surfaces being contained in an at least partially closed tang receiving recess means; tang pocket clearing and saw chain stabilizing means including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess means said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and wave vibratIon dampening means including said at least partially closed tang receiving recess means having side wall portions operable to engage opposite sides of a saw chain tang, said at least partially closed tang receiving recess means being displaced in opposite circumferential directions from at least some of said open sided tang receiving recess means.
 3. A sprocket as described in claim 2 further comprising: cutting discharging, outlet means carried by at least one side wall portion of said at least partially closed tang receiving recess means; said outlet means being circumferentially coextensive with a radially inwardly converging base portion of said at least partially closed recess means and diverging circumferentially and radially of said sprocket means in a direction axially outwardly thereof; and common body means unitizing and defining said at least partially closed tang receiving recess means and said open sided, chain saw tang receiving recess means.
 4. In a sprocket operable to support and drive an articulated saw chain having sprocket engaging tangs carried by chain links, the improvement comprising: hub means; an even numbered plurality of open sided, saw chain tang receiving, recess means spaced circumferentially about said hub means and opening generally radially outwardly thereof, said open sided recess means each including at least one wholly unobstructed, laterally open side; a single, partially closed, saw chain tang receiving recess means opening generally radially outwardly thereof, said at least partially closed tang receiving recess means having axially spaced side wall portions operable to engage opposite sides of a saw chain cutter tang; friction reducing and chain centering means including an odd number of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw chain, lateral movement restraining properties, some, but not all, of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and at least one of said tang engaging surfaces being contained in an at least partially closed tang receiving recess means; tang pocket clearing and saw chain stabilizing means including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess means, said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and wave vibration dampening means including said at least partially closed tang receiving recess means having side wall portions operable to engage opposite sides of a saw chain tang, said at least partially closed tang receiving recess means being displaced in opposite circumferential directions from at least some of said open sided tang receiving recess means, and said at least partially closed tang receiving recess means having axially spaced side wall portions extending circumferentially in opposite directions to define closed side wall portions of open sided recess means displaced circumferentially from said at least partially closed tang receiving recess means.
 5. In a chain saw including a sprocket drivingly supporting an articulated saw chain having sprocket engaging tangs, the improvement in said chain saw comprising: articulated saw chain means including sprocket engaging tangs; sprocket hub means; a plurality of open sided, saw chain tang receiving, recess means spaced circumferentially about and carried by said hub means and opening generally radially outwardly thereof, said open sided recess means each including at least one wholly unobstructed, laterally open side; at least one partially closed saw chain tang receiving recess means carried by said hub means and opening generaLly radially outwardly thereof, said at least partially closed tang receiving recess means having axially spaced side wall portions engageably disposed on opposite sides of a saw chain cutter tang; friction reducing and chain centering means including an odd number of saw chain tang engaging surfaces contained in tang receiving recess means having diverse, saw chain, lateral movement restraining properties, some, but not all, of said tang engaging surfaces being contained in some of said open sided tang receiving recess means, and at least one of said tang engaging surfaces being contained in an at least partially closed tang receiving recess means; tang pocket clearing and saw chain stabilizing means including a series of at least some of said open sided, tang receiving recess means alternating with said at least one partially closed tang receiving recess means said at least partially closed tang receiving recess means being operable to engage opposite sides of a saw chain tang while an adjacent one of said open sided recess means is operable to engage only one side of another chain saw tang; and wave vibration dampening means including said at least partially closed tang receiving recess means having side wall operable to engage opposite sides of a saw chain tang, said at least partially closed tang receiving recess means being displaced in opposite circumferential directions from at least some of said open sided tang receiving recess means. 